This is a national phase filing of the Application No. PCT/DE98/02370, which was filed with the Patent Corporation Treaty on Aug. 12, 1998, and is entitled to priority of the German Patent Application 197 35 120.4, filed Aug. 13, 1997.
The present invention relates to the use of thiol compounds for the inactivation of viruses in a cell-free environment, especially in the blood, blood plasma, blood serum, conserved blood, blood products, cell culture liquids and nutrient media and when applied onto the surface of plants and animals. In this connection, viral inactivation occurs without requiring cell metabolism.
Methods of viral inactivation, which have been common by now, comprise the irradiation with radiation rich in energy, such as U.V. light and X-rays. In this case, the objective is to damage nucleic acid molecules in the viral genome to thereby reduce the information content of the viral genetic information. By preceding staining of the viral genome using dyes which can penetrate the viral envelope (e.g., neutral red or proflavines), the viral genome can already be influenced by visible light. The treatment of virus suspensions with formaldehyde, used in viral inactivation to obtain viral vaccines, also leads predominantly via a destruction of the viral genome to a reduction of the infectiosity of these viruses. Thus, said treatment methods influence substantially the genetic material of the virus, they do not influence the composition of the viral envelope and the capability of the virus to penetrate the host cell.
Methods which prevent the attachment of the virus to its host cellxe2x80x94i.e., the first step of the process of infection-require a modification of the viral coat proteins. Such methods are, e.g., the separation of the outer viral envelope of what is called xe2x80x9cenveloped virusesxe2x80x9d by the addition of ether or detergents such as Nonidet P40, Triton X100 or sodium dodecyl sulfate (SDS). Many disinfectants which are used successfully to combat bacteria, such as chlorine compounds, have no influence on the replication of viruses.
However, there are also chemical agents having both an antibacterial effect and an antiviral effect. For example, formalin and in certain viruses also alcohols (ethanol, isopropanol) have an antiviral effect at high concentrations. However, these compounds can only be used for the purpose of disinfection. Their use, e.g., for viral inactivation in blood and blood products is not possible, since these substances having a cytotoxic and denaturing effect also destroy the blood proteins and thus prohibit, or make impossible, a further use of the derived products and their application in patients. In addition, said substances are not suitable for viral inactivation on the surface of plants, since they would kill the plant.
An essential requirement for the inactivation of viruses which are located in the direct vicinity of living cells (e.g., on the leaves of planes) or which occur in liquids in contact with living cells, is represented by the fact that the virus-inactivating agent has no cytotoxic properties.
Therefore, it is the object of the present invention to provide agents for viral inactivation in liquids (particularly in the blood, blood plasma, blood serum and blood products, cell culture liquids, nutrient media) and on the surface of plants and animals, which distinguish themselves by a low cytotoxic and/or denaturing effect. In contrast to the use of radiation rich in energy, the target of the antiviral effect is not the viral nucleic acid but the influence of viral surface proteins to already prevent the virus from entering into the host cell.
The invention relates to the use of thiol compounds in viral inactivation in a cell-free environment, especially in the blood, blood plasma, blood serum, conserved blood, blood products, cell culture liquids and nutrient media and to the application of said compounds on the surface of plants and animals. Viral inactivation occurs without requiring cell metabolism.
FIG. 1 shows the syncytia formation of HIV-infected H9 cells after pre-incubation of the virions with NAC.
FIG. 2 shows an EIA test of untreated HBsAg with 50 mM NAC-treated HBsAg, untreated HBsAg and with 50 mM NAC-treated HBeAg.
FIG. 3 shows a reduction of the infectiosity of vaccinia viruses following NAC treatment.
FIG. 4 shows removal of excess NAC by dialysis.